[mythtvnz] CF card as system drive
Kenneth Dixon
kenneth.b.dixon at gmail.com
Sun Nov 22 00:12:14 GMT 2009
Ok, its done.
After spending all yesterday failing to get software RAID (mdadm)
going and booting, I tried SATA RAID (fakeraid) which is now supported
in the Ubuntu installer which made life a lot easer. For anyone who
needs to move their old system disk over to a new raid disk, here is
an outline of how I did it:
_____________________________________________________________________________________________
Installation:
1) On boot enter the BIOS and setup your raid array. I my case it was
to parts, telling the BIOS to put the SATA controler into RAID mode,
then rebooting entering into the raid utility (Ctrl-l in my case) and
setting up the array which was RAID-0.
2) Insert the Mythbuntu Install CDROM and boot into it and start the
install procedure. In the partition manager select 'use entire disk'
and select your newly created raid array. It will have a funny name,
mine was pdc_bdceajdhcj. continue the install as normal. Do not reboot
when done (or if you have already, just boot into the install disk
again).
3) Open a terminal window, and mount both your old and new drives.
cd /media
sudo mkdir /media/old
sudo mount /dev/sdxy /media/old
# y being the disk letter and x being the partition number of your old
disk (in my case /dev/sdc1)
sudo mkdir /media/new
sudo mount /dev/mapper/raidArrayNameAndPartitionNumber
# raidArrayNameAndPartitionNumber being the name of your new raid
array and the partition ubuntu was installed to ( in my case
/dev/mapper/pdc_bdceajdhcj1)
4)Copy your old Mythbuntu installation on top of your new one. In this
case I excluded my old grub settings in case it broke things, and also
my recordings directory because it belongs back on my big slow drive
anyway (and it wouldn't fit on my new one).
sudo rsync -a --progress --exclude="/etc/grub.d"
--exclude="/etc/default/grub" --exclude="/var/lib/mythtv/recordings"
--exclude="/boot" --exclude="/etc/fstab" /media/old/ /media/new/
5) reboot, make sure your BIOS is pointing to your RAID array as the boot drive.
_____________________________________________________________________________________________
OK that's the installation, now for the performance results. I have
included my laptop HDD and old MythTV system disk for comparison,
attached is an HTML created from Bonnie++ with more results:
_____________________________________________________________________________________________
Benchmarks: (also see attached HTML)
sudo hdparm -tT /dev/sda
Laptop HDD (ST9160821AS):
Timing cached reads: 7042 MB in 1.99 seconds = 3530.74 MB/sec
Timing buffered disk reads: 134 MB in 3.03 seconds = 44.22 MB/sec
Desktop HDD (WDC-Green)
Timing cached reads: 2046 MB in 2.00 seconds = 1023.08 MB/sec
Timing buffered disk reads: 192 MB in 3.01 seconds = 63.70 MB/sec
Silicon Power 8GB SSD
Timing cached reads: 2202 MB in 2.00 seconds = 1100.97 MB/sec
Timing buffered disk reads: 242 MB in 3.02 seconds = 80.10 MB/sec
Silicon Power 8GB SSD - Software RAID0
Timing cached reads: 2352 MB in 2.00 seconds = 1175.64 MB/sec
Timing buffered disk reads: 378 MB in 3.01 seconds = 125.52 MB/sec
Silicon Power 8GB SSD - Fakeraid RAID0
Timing cached reads: 2378 MB in 2.00 seconds = 1189.31 MB/sec
Timing buffered disk reads: 340 MB in 3.02 seconds = 112.68 MB/sec
_____________________________________________________________________________________________
Boot Time:
Boot time WDC-Green
88 Seconds
Boot time SSD-FakeRaid-Raid0
70 Seconds total
25 Seconds of that was for the Bios RAID utility "Scanning Disks"
_____________________________________________________________________________________________
Drive specs:
sudo hdparm -I /dev/sda
/dev/sda:
ATA device, with non-removable media
Model Number: eSATA SSD
Serial Number: 0000000000000000026F
Firmware Revision: 081016
Standards:
Used: ATA/ATAPI-7 T13 1532D revision 4a
Supported: 8 7 6 5 & some of 8
Configuration:
Logical max current
cylinders 15620 15620
heads 16 16
sectors/track 63 63
--
CHS current addressable sectors: 15744960
LBA user addressable sectors: 15744960
Logical/Physical Sector size: 512 bytes
device size with M = 1024*1024: 7687 MBytes
device size with M = 1000*1000: 8061 MBytes (8 GB)
cache/buffer size = unknown
Nominal Media Rotation Rate: Solid State Device
Capabilities:
LBA, IORDY(can be disabled)
Standby timer values: spec'd by Standard, no device specific minimum
R/W multiple sector transfer: Max = 1 Current = ?
Recommended acoustic management value: 128, current value: 254
DMA: mdma0 mdma1 mdma2 udma0 udma1 udma2 udma3 udma4 *udma5
Cycle time: min=120ns recommended=120ns
PIO: pio0 pio1 pio2 pio3 pio4
Cycle time: no flow control=120ns IORDY flow control=120ns
Commands/features:
Enabled Supported:
* SMART feature set
* Power Management feature set
* Write cache
Look-ahead
* Mandatory FLUSH_CACHE
* Gen1 signaling speed (1.5Gb/s)
* Gen2 signaling speed (3.0Gb/s)
Checksum: correct
_____________________________________________________________________________________________
Conclusion:
Well I'm pretty happy with the results,
- I was able to keep my old system with its tweaks
- MythTV boots significantly faster
- MythTV is infinitely more responsive (channel changing and general
navigation).
- MythTV is more stable (Use to crash a lot when changing channels,
this is no longer the case. I'm not sure if this was due to the
slowness of my old drive or having my livetv directory on the system
drive or both.)
- Uses less power as I can now spin down my recordings drive when not
in use and the SSD's don't use much power at all.
- Cost all up was $137, including: 2xSSD(8GB), 1xESATA Bracket and
shipping. (This compares pretty well with the 'Proper' SSD's currently
on the market)
Reservations:
- Despite having 'SSD' in the title, the drives look to be designed as
transportable storage rather than system disks and I'm not sure the
wear-levelling technology on them is up to the spec of a proper SSD.
Hopefully by time they crap out SSD prices will have come down enough
to buy a real one.
Any questions? don't hesitate to ask.
Ken.
2009/11/19 Noel & Di <noel at igrin.co.nz>:
> Aha! yes I await your report with great anticipation.
>
>
> Kenneth Dixon wrote:
>> I ordered a couple of these last week to do something similar
>> http://pricespy.co.nz/product.php?p=436517
>> Silicon Power eSATA/USB SSD 8GB.
>> I was going to software RAID them to try and get some extra performance.
>> Seem to be good value at ~$55, claim 90MB/s read, but reviews suggest
>> closer to 60MB/s.
>> One peculiarity is that most esata ports don't provide power, so must
>> be powered by usb.
>> If you can wait till the weekend I will tell you how they perform.
>>
>> Ken
>>
>> 2009/11/18 Steve Hodge <stevehodge at gmail.com>:
>>
>>> On Wed, Nov 18, 2009 at 4:38 PM, Noel & Di <noel at igrin.co.nz> wrote:
>>>
>>>> Steve Hodge wrote:
>>>>
>>>>> According to pricespy 8G CF cards start around $40.
>>>>>
>>>>> Of course it may be that the original poster already has a CF card
>>>>> spare as well.
>>>>>
>>>> So the consensus is an 8GB card should be enough, and an SD class 6
>>>> (6MB/S) is fast enough for a system drive?
>>>> It is understood the boot up time is irrelevant because the machine runs
>>>> 24/7 anyway.
>>>>
>>> Speed shouldn't be a problem. Whether 8GB is enough depends on what else
>>> you're installing. My system has a 10GB root partition which is 80% full,
>>> but I run Gentoo which chews up a couple of gig in package management. If
>>> you're using a distro with binary packages and only running Myth I think
>>> you'll be fine with 8GB.
>>>
>>> Cheers,
>>> Steve
>>>
>>>
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>>
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